When one chooses the lifestyle of a bush rat there are a number of decisions that require careful consideration. A primary decision is “How I am going to provide heat?” Historically and currently the most common and practical solution for the British Thermal Unit (BTU) need is firewood. Some say firewood makes heat twice, first when you cut it and second when you burn it!
In the boreal forest of the Talkeetna Territory there are two practical choices: paper birch and white spruce. Both are readily available and renewable. These woods are inexpensive if you cut your own. Some choose to split the wood for faster drying.
Splitting requires an additional step of handling, more work. Cutting the wood in the round and putting a slit cut down the side of the log goes a long way toward accelerating the drying
process. University of Alaska says anything below thirty to thirty-
three percent moisture has the most beneficial BTU value.
An old Sourdough’s trick for winter/spring cutting reduces
wood moisture substantially, particularly in the paper birch.
Go out and fell the tree when the crust is on the snow in early
morning; you can walk out there without snowshoes. Let the
tree lie, untrimmed, until May, when the sprouting of leaves
will draw most of the moisture out. Then limb the tree and cut
into logs. Using this method, you can reduce moisture to twenty
to twenty-two percent.
It is important to understand three characteristics of wood
when harvesting for firewood. Density, resin content and moisture
content are characteristics that vary among species and
between trees of the same species. The variability contributes
to differences in weight, intensity and rate of combustion, and
thus the amount of heat in a given volume of wood. Density
is usually expressed in pounds per cubic foot; the denser the
wood the higher the heat output.
Resins are highly flammable and can result in higher heat
output. Moisture content is usually expressed as green or air
dry. Paper birch has a resin moisture content of about eighty
percent, white spruce about ninety percent. The recommended
moisture percentage for efficient burning is thirty percent
or less. The drier the wood, the higher the heat output.
The usual required amount of wood for our area and size
of home is six cords of firewood. A cord is eighty-five to ninety
cubic feet, stacked four feet high, four feet deep, and eight
feet long. Surprisingly, the weight of a cord of birch is 3,500
pounds and white spruce is 2,500 pounds. A cord of paper
birch provides 25.4 million BTU per cord, according to a table
on the energy content of boreal forest trees. This number was
prepared by George Sampson, a former Institute of Northern
Forestry Research forester.
Staying warm as a bush rat is not a labor of love, but a love
of labor.
